2017-05-11 21:43 GMT+08:00 Wanpeng Li <kernel...@gmail.com>: > 2017-05-11 20:24 GMT+08:00 Paolo Bonzini <pbonz...@redhat.com>: >> >> >> On 11/05/2017 14:07, Zhoujian (jay) wrote: >>> - * Scan sptes if dirty logging has been stopped, dropping those >>> - * which can be collapsed into a single large-page spte. Later >>> - * page faults will create the large-page sptes. >>> + * Reset each vcpu's mmu, then page faults will create the >>> large-page >>> + * sptes later. >>> */ >>> if ((change != KVM_MR_DELETE) && >>> (old->flags & KVM_MEM_LOG_DIRTY_PAGES) && >>> - !(new->flags & KVM_MEM_LOG_DIRTY_PAGES)) >>> - kvm_mmu_zap_collapsible_sptes(kvm, new); > > This is an unlikely branch(unless guest live migration fails and > continue to run on the source machine) instead of hot path, do you > have any performance number for your real workloads?
I find the original discussion by google. https://lists.nongnu.org/archive/html/qemu-devel/2017-04/msg04143.html You will not go to this branch if the guest live migration successfully. Regards, Wanpeng Li
